Harvesting machine with under-vine closure

ABSTRACT

An under-vine closure assembly, for harvesting machines adapted to straddle and move along a row of fruited plants, having flat closure wings mounted in overlapping relation on the machine conveyors and extending upwardly and inwardly to the centerline of the machine. The closure wings are each pivotally mounted on the conveyors for pivotal movement only in the closure planes away from and back to space-closing position and are made of flexible material to enable the free ends to flex up or down a substantial distance without breakage, and shaped to allow immediate free return after passing an obstacle which forced the one closure wing open. The closure wings are biased against movement from a normal space-closing position either in the opening direction or in an overtravel-upon-closing direction by a spring providing a progressively increasing bias as the amount of movement from normal position increases in either direction and wherein substantially more force is required to move the closure wings in an opening direction than is required to move the closure wings in an overtravel direction.

United States Patent Claxton et al.

[ Feb. 18. 1975 HARVESTING MACHINE WITH UNDER-VINE CLOSURE [75] Inventors: Gerald L. Claxton, Lafayette; Barris .l. Evulich, Cupertino, both of Calif.

[73] Assignee: Up-Right, lnc., Berkeley, Calif.

[22] Filed: May 30, 1973 {21] Appl. No.: 365,267

Related U.S. Application Data [63] Continuation-impart of Ser. No. 292,084, Sept. 25,

1972, abandoned.

[52] U.S. Cl. 56/330 [51] Int. Cl A0lg 19/00 [58] Field of Search... 56/330, 331, 328 R, 329 TS;

Primary Examiner-Louis G. Mancene Assistant ExaminerJ. N. Eskovitz Attorney, Agent, or Firm-Phillips, Moore, Weissenberger, Lempio & Strabala 571 h ABSTRACT An under-vine closure assembly. for harvesting machines adapted to straddle and move along a row of fruited plants, having flat closure wings mounted in overlapping relation on the machine conveyors and extending upwardly and inwardly to the centerline of the machine. The closure wings are each pivotally mounted on the conveyors for pivotal movement only in the closure planes away from and back to spaceclosing position and are made of flexible material to enable the free ends to flex up or down a substantial distance without breakage, and shaped to allow imme diate free return after passing an obstacle which forced the one closure wing open. The closure wings are biased against movement from a normal space closing position either in the opening direction or in an overtravel-upon-closing direction by a spring providing a progressively increasing bias as the amount of movement from normal position increases in either direction and wherein substantially more force is required to move the closure wings in an opening direction than is required to move the closure wings in an overtravel direction.

11 Claims, 10 Drawing Figures FATENTED FEB 1 SHEET 2 OF 4 FIG....5

PATENTED FEB 1 3. 866 .401

SHEET 30F 4 PATENTEU 3,866,401

sum 40? 4 HARVESTING MACHINE WITH UNDER-VINE CLOSURE CROSS-REFERENCE TO RELATED APPLICATION This application is a continuation-in-part of our earlier application, Ser. No. 292,084, filed on Sept. 25, 1972, and now abandoned.

BACKGROUND OF THE INVENTION This invention relates to fruit-harvesting machines of the type that straddle and move along a row of fruitbearing vines or bushes to harvest fruit therefrom. Such machines have shaking or striking means to dislodge the fruit from the plants, so that the fruit drops toward the ground. In order to gather the fruit, a closure means must be provided between the plants and the ground to intercept the falling fruit and direct it to the conveyors of the machine. If an efficient closure is not provided, a portion of the harvested fruit will fall there through onto the ground and be wasted.

The provision of an efficient closure is made difficult since a large amount of the fruit drops on the centerline of the row, at the very location where the closure must be capable of opening to allow passage therebetween of the trunks or posts that support the fruit-bearing portions of the plants.

The most efficient closure is one which projects under the plants from both sides to the centerline of the row, and which will provide the least opening therethrough to allow the stationary trunks and posts to pass between the closure halves, so that the maximum amount of the falling fruit will be intercepted by the closure and diverted thereby, without damage, to each side so the fruit may be conveyed by belt conveyors or the like.

One approach to the problem is the mechanical array of pivoted shutters, as shown in U.S. Pat. No. 3,126,692 to Weygandt et al., issued Mar. 31, 1964, and the U.S. Pat. No. 3,538,694 to Holloway, issued Nov. 10, 1970. Actual field use of these devices has shown a number of deficiencies. The rigid shutters are often jammed in open position by berries or branches caught between adjacent shutters. Oftentimes contact of the shutters by angular branches on the trunks or vines or contact with the berm of ground underneath the shutters will force the shutters downwardly or upwardly: either breaking the shutters, which opens up a large gap in the closure; or, permanently deforming the shutters, causing them to jam open, thereby leaving a large open gap.

In addition, Weygandt uses rigid stops to stop return movement of his shutters which often causes breakage of the shutter and its mount. Holloway reduces this particular problem somewhat by reducing the return force on the shutters when opened fully and by using a stiff spring to resist overtravel. However, reducing the return force reduces the speed of closure, and in actual field operations the stiff spring used to resist overtravel does subject the shutters to substantial shock upon closing.

Another approach to the problem, which has proven to be only partially effective, is the use of a pair of stiff rubber fins, meeting at the centerline of the row and each mounted at an angle to cause the falling fruit to roll or slide outwardly and downwardly to the conveyors. Such approach is typified in the U.S. Pat. No. 3,165,879 to Chapin, issued Jan. 19, 1965. In practice,

it has been found that if the rubber fins are stiff enough to extend outwardly at the desired angle, they are not flexible enough to wrap around the vine trunk or post as it wipes thereon during passage thereby. The necessary stiffness creates excessive friction and wear on the fins, as well as excessive damage to the posts and trunks. Additionally, a long, large open gap is created between the mating edges of the fins as a trunk or post passes therebetween, with a consequent loss of fruit through the gap. Further, if a large post or trunk is encountered, one or both fins may be bent down, rather than up, and will spill all of the fruit on the ground. If the fins are made flexible enough to minimize the friction, wear and creation of a gap, then either they will not be stiff enough to catch the fruit if mounted at a low angle of inclination or else they will have to be mounted at such a steep angle of inclination that only high plants can be harvested.

Still another approach is the flexible fin closure shown in U.S. Pat. No. 3,601,965, issued to Kaessbohrer and Horn on Aug. 31, 1971. This solved many of the problems of the previous fin closure, but in practice it has been found that this device does not provide a sufficient range of lateral opening and closing beneath the vine to catch the falling fruit when large, old, crooked or misaligned vine-trunks are encountered, or when the stumps of branches protrude in such manner as to force the fin closures so widely apart that there are large openings through which the fruit can fall on the ground.

A further approach to a flexible closure is the system shown in U.S. Pat. No. 3,690,054 to De Carlo et al., is-

move the end of the plate downwardly, the entire plate tilts, spilling all of the fruit thereon onto the ground.

SUMMARY OF THE INVENTION The closure problems presented by vineyards having large, crooked, stumpy and misaligned trunks have been solved by providing a closure which comprises a plurality of flat overlapping wings mounted at spaced intervals along the conveyors, to form a continuous closure surface. The wings are individually pivotally mounted at one end to a conveyor with the other end being resiliently biased towards the centerline of the row, the wing being individually pivoted away from the centerline, against the bias of the spring, by engagement with posts and trunks. The springs are designed so that the returning force of the spring progressively increases as the wing is pushed further from its relaxed position. By increasing the returning force, more rapid closing is achieved. Also, there is much less likelihood that the wings will stick in open position after the obstruction is passed, which causes fruit loss onto the ground. The springs are also designed to cushion the closing of the wings so that the wings will not be subject to abrupt and damaging shock upon closing. Additionally, the wings are individually flexible so that their free ends can also flex up or down a substantial distance without breakage or permanent deformation. The wings are made so that their trailing edges allow immediate and rapid return once the obstruction has been passed. The combination of the individual pivotal movement of the wings in the plane of the closure and the individual flexibility of the wing ends in a direction perpendicular to the closure plane enables the closure members to pass by very irregular trunks and posts with a minimum of gap being opened and without jamming. In addition to the individual movement of the wings, the closures are suspended on the harvester from above so that the closures can float as a unit sideways of the machine and thus seek the centerline of the row in spite of steering errors of the driver or tilting of the row in spite of steering erros of the driver or tilting of the machine because of unevenness of the ground.

The present combination of sidewards floating closures made up of multiple, flexible and pivotal wings provides: a minimal closure opening, with minimal fruit loss; a significant elimination of jamming by canes or branches wedging between the closure wings; and, a significant elimination of breakage of the closure elements or their mountings.

Other objects and advantages will become apparent in the course of the following detailed description.

BRIEF DESCRIPTION OF THE DRAWINGS In the drawings, forming a part of this application, and in which like parts are designated by like reference numerals throughout the same,

FIG. 1 is an elevational view of a fruit-harvesting machine utilizing the closure of the present invention;

FIG. 2 is a plan view of a portion of the machine of FIG. 1 showing the manner in which each closure wing is mounted to the conveyor;

FIG. 3 is a generally elevational detail, illustrating the manner in which the closure spring is mounted on the closure wing and conveyor;

FIG. 4 is an elevational view of the portion of the machine shown in FIG. 2;

FIG. 5 is a plan view of the closure members illlustrating the manner in which the closure wings are pivoted away from the centerline by irregular trunks;

FIG. 6 is a view in elevation of the closure members illustrating the manner in which the free ends of the closure wings may be flexed upwardly or downwardly by irregular trunks;

FIG. 7 illustrates the shape of the closure spring when the closure wing is in its normally closed position;

FIG. 8 illustrates the shape of the closure spring when the closure wing is opening;

FIG. 9 illustrates the shape of the closure spring when the closure wing has traveled beyond its normally closed position;

FIG. 10 is a graph of the forces exerted by the closure spring on the closure wing during opening movement and during overtravel beyond its normally closed position.

DESCRIPTION OF THE PREFERRED EMBODIMENT As best seen in FIG. 1, the harvesting machine 10 comprises a tunnel-shaped main frame 11 mounted on wheels 12, adapted to straddle and move longitudinally along a row of fruited plants. Conventional strikers or shakers, not illustrated, are mounted on the frame and operated to engage the plants and dislodge the. fruit therefrom so that it may fall towards the ground. A pair of conveyors 13 and 13 are carried on the machine, these conveyors extending lengthwise of the machine parallel to and one on each side of the centerline of the machine. Conveyors l3 and 13' have closure members 14 and 14', respectively, mounted thereon, the closure members extending inwardly and upwardly towards the centerline of the machine. Each end of conveyor 13 is supported by bracket 15, which is suspended from main frame 11 by two parallel support members 16 and 17 which are pivotally connected to the main frame and the bracket 15, thus enabling the conveyor 13 and closure 14 to float sidewards as a unit. towards and awawy from the centerline of the machine. Tension springs 18 extending between and connected to the support members 16 and 17 resiliently bias the conveyor and closure towards the centerline of the machine. Turnbuckles 19 enable the bias force to be ad justed as desired. Conveyor 13' and closure 14 are similarly mounted for sideways floating movement, conveyor 13 and closure 14 and the elements associated therewith are identical to, but reversed from, conveyor 13 and closure 14. Primed reference numerals will be used herein to indicate elements associated with conveyor 13' and closure 14 which correspond to elements identified by unprimed reference numerals. FIGS. 2 and 4 illustrate the manner in which the individual closure wings 20 of closure 14 are mounted on conveyor 13. Conveyor 13 comprises an open-topped pan or frame 21 which supports a continuous conveyor belt 22 for longitudinal movement therein. Typically, the conveyor belt is provided with upright cleats 23, transversely thereof and spaced along the belt. A closure mounting bracket 24 is fixedly mounted along the length of the inner upper edge of conveyor frame 21, the bracket having an upper flange 25 generally parallel to the plane of closure 13 and the overlapping closure wings 20 thereof. Closure wing 20 has a circular hub 26 fixedly secured to the undersurface thereof, the hub fitting within ring member 27 fixed to bracket flange 25, and being held in place therein by retainer pin 28 which extends through the hub and the radial slots 29 in ring 27. By this arrangement the closure wing 20 may pivot in the closure plane about the axis of the hub 26, this axis being normal to the closure plane.

Two spring supports are provided, one being a bolt 31 carried by closure wing 20 and having a head 31a extending therebelow and the other being a bolt 32 fixed to bracket flange 25 and having a head 32a extending thereabove. Bolts 31 and 32 are preferably equally spaced from the axis of hub 26. A flexure coil spring 33, having a plurality of helical turns 33a has two ends 33b and 3130 turned back upon themselves for securement to bolts 31 and 32. Coil spring end 33b extends from end turn 33d and lis generally in the plane definedby end turn 33d. Similarly, coil spring end 330 extends from end turn 33c and lies generally in the plane defined by end turn 33c. Preferably coil spring ends 33b and 33c are generally tangent to the end turn from which they extend, so that end 33b extends from the top of coil 33 and end 33c extends from the bottom of coil 33. With this arrangement the coil mounting bolts 31 and 32 can be made quite short so that there will be a vertical clearance between the heads thereof to prevent engagement of the bolts on opening movement of the closure wing and also so that less snagging of vines will occur during harvesting operations.

FIGS. 7-9 illustrate the operation of spring 33, FIG. 7 showing the spring at its relaxed position when the closure wing to which it is secured is at its normally closed position, i.e., as shown in FIG. 2. As the closure wing pivots away from the centerline of the machine, the bolt 31 on the closure wing is moved towards bolt 32 on the conveyor frame, as in FIG. 8, applying force to the coil spring ends 33b and 33d which is exerted on the coil spring through the moment arm d, to cause the spring 33 to flex so that its normally straight axis becomes arcuate, bowing towards hub 26. As is seen from FIG. 8, the coil turns remain in contact with each other on the side of the coil away from the axis of pivotal movement 26, and open up on the side of the coil facing axis 26. Because of the geometry of the spring and spring ends and the location of the bolt supports 31 and 32 closely adjacent the end turns of the coil but offset therefrom to provide the moment arm 41,, the spring has a positive spring constant so that the more the closure wing pivots to open position the greater will be the force stored in the spring urging the closure wing back to closed position. FIG. is a graph showing the buildup of force stored in the spring as the closure wing is moved from its normally closed position to its full open position.

FIG. 9 illustrates the action of spring 33 after it has been moved back to its normal closed position, indicated by the reference line no, and the closure wing overtravels because of its inertia, i.e., to the position shown in FIG. 9. During overtravel bolt 31 on the closure wing moves away from bolt 32 on the frame applying force on the coil spring ends 33b and 33d which is exerted on the coil spring through the moment arm d to cause the spring to flex in the opposite direction, away from hub 26, with the coil turns being closed against one another on the side of the coil facing hub 26 and being open on the opposite side. As in the opening movement, the spring has a positive spring constant so that the force stored in spring 33 on overtravel will increase as the degree of overtravel movement increases. Since the length of moment arm d is considerably greater by an amount equal to the diameter of the coil spring than the length of moment arm d a correspondingly lesser force is built up in the spring during overtravel as compared to that built up in the spring for an equal degree of pivotal movement in the opening direction, as shown in FIG. 10.

With this construction a rapid and efficient closure system is achieved. As the closure wing is forced open by vines or trunks, the return force built up in spring 33 increases in accordance with the degree of opening movement. If a large space is opened up, the return force is greater so that when the obstruction is passed the spring 33 will return the closure wing to close position as quickly as possible. When the closure wing has returned to its normal position, the inertia thereof will cause it to overtravel. Rather than being stopped abruptly, the closure spring offers relatively little resistance to initial overtravel. As the overtravel continues, the spring will bring the closure wing to a smooth stop. The spring will then return the closure wing back to its normal closed position. The cushioning effect provided by the spring in overtravel operation thus enables the normal closing of the closure wing from open position to be achieved rapidly without damage to the closure wing and with less possibility that loose fruit on the closing closure wing will be thrown therefrom as the closure wing is brought to a stop.

As is illustrated, closure wing 20 is relatively thin and flat, the wing having a forward edge 36 inclined rearwardly of the machine for sliding engagement by a stationary trunk or post as the machine travels along the row in the direction indicated by the arrow in FIG. 5, and an inner edge 37 which is parallel to the centerline of the machine when the wing is in its normally biased inward position. The outer side edge 38 of wing 20 overlies the forward edge 36 and a substantial portion of the forward upper surface of the next rearward closure wing so that the next rearward closure wing may pivot a substantial distance without opening up a gap between it and the forward wing.

The closure wing 20 terminates in a trailing edge spaced from the hub 26, the traveling edge being generally perpendicular to a line from the hub to the trailing edge. Thus, as soon as the inner end 39a of the closure wing passes the obstruction which caused the wing to pivot to open position, the closure wing is free to return to closed position. Heretofore, in commercial machines, the trailing edge of corresponding closure wings have been designed to ride against the obstruction during closing movement to retard the rate of closing movement and thereby prevent closure wing damage resulting from the abrupt stopping of high speed closing of closure wing movement. In the present apparatus, however, the cushioning provided by spring 33 allows high-speed closing without damaging and thus enables the closure wing to be constructed for unretarded closing. Ideally, the trailing edge 39 would be arcuate in shape, with the center of curvature being coincident with the axis of hub 26. However, since the harvesting machine moves relative to the obstruction and since the length of the closure wing is relatively long as compared to the width, for ease in manufacturing it is preferable to shape the trailing end 39 so that it is the chord of an are having its center coincident with the axis of hub 26. In either case, the arc and the chord thereof are generally perpendicular to a line from the hub to the trailing edge.

Closure wings 20 are formed from a tough but flexible material, such as high-density polyethylene plastic. As is indicated in FIGS. 5 and 6, the major movement of the closure assembly as posts and trunks are encountered is the pivotal movement of the closure wings about their hubs 26 in the plane of closure 14. As a consequence, the wings 26 need not be as flexible as the rubber fins of the aforementioned Chapin and Kaessbohrer patents, which must flex laterally around trunks and posts. The wings 20 must, however, be flexible enough so that the inner edge 37 can flex relatively easily upwardly or downward an amount to pass over or under branches on the trunks without breakage or permanent deformation of the wing. It has been found that closure wings of high-density polyethylene material will have more than adequate stiffness for normal collection of fruit dropping thereonto, while yet providing for up to six inches of upward or downward deflection of its inner edge 37 without damage to the closure wings.

The end of closure wing 20 which is mounted to bracket 24 is preferably stiffened against flexure, as by the addition of a metal plate 40 thereunder, the plate extending outwardly towards the other end as far as is desired. The wing 20 could alternatively be locally thickened to provide an increase of stiffness at the pivoted end.

FIG. illustrates the operation wherein closure wings 20a through 2011' travel along a row of plants which includes trunks 45 and 46 and horizontal vines 47 ex tending between the trunks above the closures. Closure wings 20a and 200 have already passed trunk 44 and have been pivoted back to their inward position so that their inner edges 37 and 37 are at the centerline of the row to complete the closure beneath the vine 47. Closure wings 20b and 20b have been engaged by and pivoted outwardly by trunk 45. As shown, the branch 48 has caused wing 20b to pivot outwardly a considerably greater distance than wing 20b. The stub end 49 of the branch has deflected the end of wing 20b downwardly and rides thereover. The remainder of the drawing shows the minimal gap opened up even though a very large, gnarled trunk 46 is encountered.

FIG. 6 illustrates, in elevation, the ability of the closure members to flex upwardly or downwardly upon encountering branch stubs or other similar irregularities in trunk 55. For example, the normal closure plane of closure 14 would be between the solid and dotted line positions of closure wing 20, so that the closure wing would be carried head-on into trunk stub 56. If stub 56 is so shaped that it will exert a vertical force on the wing, in addition to a sidewards, pivoting force, the wing end simply flexes so that it will ride over or under the stub, as illustrated by the solid and dotted lines. Flexure wing 20 is shown as undergoing an even greater degree of vertical flexure from the normal closure plane in the solid and dotted line positions thereof as it passes by trunk stub 57.

The vertical flexure of wings 20, as shown in FIG. 6, is also very advantageous in preventing jamming of adjacent wings in the event a branch should break off or a trailing tendril should become wedged between adjacent wings. In such event, the forward, or upper, wing simply flexes upwardly or the rearward, lower, wing flexes downwardly, or both, allowing normal scissorstype pivotal movement of the wings to take place, with the wings sliding over and under the branch or tendril therebetween until the branch works itself out or the tendril is pulled out from therebetween.

The present invention has a further significant advantage resulting from the use of closure wings that can flex upwardly or downwardly at their free ends. In present harvesting machines having pivoted closure wings or shutters on opposite sides of the machine which extend upwardly and inwardly to the centerline of the machine, the closures are designed so that there is a deflnite overlap at the centerline of the machine so that the free ends of all of the closure members on one side extend over the free ends of all of the closure members on the other side, thereby allowing the closure members on one side of the machine to pivot back and forth without being jammed by the closure members on the other side of the machine. As a result, if the conveyors are of equal height above the ground, the two sets of closure members will be inclined at different angles upwardly from the conveyors to allow the overlap. Thus, if the set of upper closure members at most efficient inclination, i.e., steep enough to move the collected fruit to the conveyor and shallow enough to collect lowhanging fruit, the set of lower closure members must be a lower, more inefficient inclination. With the present invention, the conveyors can be at the same height above the ground and the two sets of closure members can be upwardly inclined at the same, and most efficient, angle. The overlapping free ends will overlap in a random manner, the closure members on one side having their free ends some above and some below the free ends of the corresponding closure members on the other side. The flexibility of the free ends allows such random overlapping without jamming.

The present invention also enables the conveyors to be mounted on the machine so that the conveyors and closure wings may slope downwardly lengthwise of the machine and towards the front of the machine. With such arrangement, the apex of the closure planes at the forward end of the machine can be quite close to the ground to pass under and catch low-hanging fruit, while the rearward end of the conveyors can be sufflciently high above the ground as to enable the gathered and conveyed fruit to be transferred to cross-conveyor positioned under the discharge ends of the lengthwise conveyors. As the inclined conveyors are moved horizontally along the row, branch arms just above the forward end of the closures will pass over the forward closure wings and will then engage rearward closure wings and exert downward forces thereon. However, as explained previously, such downward forces will simply flex the tips of the closure wings downwardly so that they will ride under such branch arm without damage to the closure members.

Having thus described our invention, we claim:

1. A harvesting machine comprising:

a main frame adapted to straddle and move longitudinally along a row of fruit-bearing plants,

a pair of conveyor mechanisms carried by said main frame and extending along the length thereof, one on each side of the longitudinal centerline of the machine, each conveyor mechanism having a frame and a conveyor belt carried thereby,

a closure assembly secured to the inner edge of each conveyor frame, said closure assemblies forming closure planes extending inwardly and upwardly from the conveyor frames towards the longitudinal centerline of said machine.

each closure assembly comprising a plurality of flat,

overlapping wing members spaced along the conveyor frame associated therewith and lying in the closure plane associated therewith, each wing member being separately and pivotally mounted at one end thereof for confined movement of said one end of said wing member in said closure plane and for movement of the other end of the wing member in said closure plane towards and away from said longitudinal centerline, and spring means connected to and interposed between each of said wing members and said frame for yieldingly maintaining each such wing member in a normal space-closing position while allowing each wing member to pivot against the bias of said spring means from said normal space-closing position in a space-opening direction away from said longitudinal centerline and to pivot against the bias of said spring means from said normal space-closing position in an overtravel direction towards said longitudinal centerline, said spring means having a first positive spring rate effective to resist pivot movment of the corresponding wing member in said space-opening direction away from said normal position with a progressively increasing force as the increasing force as the degree of space-opening movement increases and also having a second positive spring rate effective to resist pivotal movement of said wing member in said overtravel direction away from said normal position with a progressively increasing force, said first spring rate being greater than said second spring rate.

2. A harvesting machine set forth in claim 1 wherein each wing member terminates in a trailing edge spaced from the pivotal mounting of said wing member, the trailing edge being generally perpendicular to a line from the pivotal mounting to said trailing edge.

3. A harvesting machine as set forth in claim 1 wherein said wing members are formed from plastic material having sufficient flexibility to enable said other ends of said wing members to flex upwardly or downwardly a substantial distance transverse to said closure planes.

4. A harvesting machine as set forth in claim 3 wherein both of said conveyors are the same height from the ground and wherein said closure planes are equally inclined inwardly and upwardly towards the longitudinal centerline of said machine and are overlapped at said centerline, with some wing members in one closure assembly being overlapped at random on wing members in the opposite closure assembly and vice versa.

5. A harvesting machine as set forth in claim 3 wherein each wing member terminates in a trailing edge spaced from the pivotal mounting of said wing member, the trailing edge being generally perpendicular to a line from the pivotal mounting to said trailing edge.

6. A harvesting machine as set forth in claim 1 wherein said spring means comprises a coil spring having a plurality of helical turns, said coil spring having a first end extending from one end turn and projecting outwardly from said coil in generally the same plane defined by said one end turn and a second end extending from the other end turn and projecting outwardly from said coil in generally the same plane defined by said other end turn, said first end being secured to a wing member and said second end being secured to said conveyor frame, with the axis of said coil spring being offset from the line between the points of securement of said coil spring to said wing member and said conveyor frame for substantial transverse flexure of said coil spring upon pivotal movement of said wing member in either direction from said normal position.

7. A harvesting machine as set forth in claim 6 wherein each wing member terminates in a trailing edge spaced from the pivotal mounting of said wing member, the trailing edge being generally perpendicular to a line from the pivotal mounting to said trailing edge.

8. A harvesting machine as set forth in claim 6 wherein said wing members are formed from plastic material having sufficient flexibility to enable said other ends of said wing members to flex upwardly or downwardly a substantial distance transverse to said closure planes.

9. A harvesting machine as set forth in claim 8 wherein each wing member terminates in a trailing edge spaced from the pivotal mounting of said wing member, the trailing edge being generally perpendicular to a line from the pivotal mounting to said trailing edge.

10. A harvesting machine as set forth in claim 6 wherein said first and second ends of said coil spring are generally tangent to the end turns from which they extend.

11. A harvesting machine comprising:

a main frame adapted to straddle and move longitudinally along a row of fruit-bearing plants,

a pair of conveyor mechanisms carried by said main frame and extending along the length thereof, one on each side of the longitudinal centerline of the machine and both at the same height above the ground, each conveyor mechanism having a frame and a conveyor belt carried thereby,

a closure assembly secured to the inner edge of each conveyor frame, said closure assemblies forming closure planes extending inwardly and upwardly at the same angle of inclination from the conveyor frames towards the longitudinal centerline of said machine,

each closure assembly comprising a plurality of flat,

overlapping wing members spaced along the conveyor frame associated therewith and lying in the closure plane associated therewith, and including means for pivotally mounting each wing member at one end thereof for movement of the opposite free end of the wing member towards and away from said longitudinal centerline with movement of said one end of said wing member being confined to movement in said closure plane,

the free ends of said wing members on opposite sides of said longitudinal centerline being normally and randomly overlapped at said centerline, with some wing members on one side of said centerline being overlapped on wing members on the other side of said centerline and vice versa,

spring means associated with each wing member for resiliently biasing said free end of said wing members towards said longitudinal centerline,

said wing members being formed from plastic mate rial having sufficient flexibility to enable said free ends of said wing members to flex upwardly or downwardly a substantial distance transverse to said closure planes and to enable said wing members to overlap at random at said longitudinal centerline after being pivoted away from and returned 

1. A harvesting machine comprising: a main frame adapted to straddle and move longitudinally along a row of fruit-bearing plants, a pair of conveyor mechanisms carried by said main frame and extending along the length thereof, one on each side of the longitudinal centerline of the machine, each conveyor mechanism having a frame and a conveyor belt carried thereby, a closure assembly secured to the inner edge of each conveyor frame, said closure assembliEs forming closure planes extending inwardly and upwardly from the conveyor frames towards the longitudinal centerline of said machine. each closure assembly comprising a plurality of flat, overlapping wing members spaced along the conveyor frame associated therewith and lying in the closure plane associated therewith, each wing member being separately and pivotally mounted at one end thereof for confined movement of said one end of said wing member in said closure plane and for movement of the other end of the wing member in said closure plane towards and away from said longitudinal centerline, and spring means connected to and interposed between each of said wing members and said frame for yieldingly maintaining each such wing member in a normal space-closing position while allowing each wing member to pivot against the bias of said spring means from said normal space-closing position in a space-opening direction away from said longitudinal centerline and to pivot against the bias of said spring means from said normal spaceclosing position in an overtravel direction towards said longitudinal centerline, said spring means having a first positive spring rate effective to resist pivot movment of the corresponding wing member in said space-opening direction away from said normal position with a progressively increasing force as the increasing force as the degree of space-opening movement increases and also having a second positive spring rate effective to resist pivotal movement of said wing member in said overtravel direction away from said normal position with a progressively increasing force, said first spring rate being greater than said second spring rate.
 2. A harvesting machine set forth in claim 1 wherein each wing member terminates in a trailing edge spaced from the pivotal mounting of said wing member, the trailing edge being generally perpendicular to a line from the pivotal mounting to said trailing edge.
 3. A harvesting machine as set forth in claim 1 wherein said wing members are formed from plastic material having sufficient flexibility to enable said other ends of said wing members to flex upwardly or downwardly a substantial distance transverse to said closure planes.
 4. A harvesting machine as set forth in claim 3 wherein both of said conveyors are the same height from the ground and wherein said closure planes are equally inclined inwardly and upwardly towards the longitudinal centerline of said machine and are overlapped at said centerline, with some wing members in one closure assembly being overlapped at random on wing members in the opposite closure assembly and vice versa.
 5. A harvesting machine as set forth in claim 3 wherein each wing member terminates in a trailing edge spaced from the pivotal mounting of said wing member, the trailing edge being generally perpendicular to a line from the pivotal mounting to said trailing edge.
 6. A harvesting machine as set forth in claim 1 wherein said spring means comprises a coil spring having a plurality of helical turns, said coil spring having a first end extending from one end turn and projecting outwardly from said coil in generally the same plane defined by said one end turn and a second end extending from the other end turn and projecting outwardly from said coil in generally the same plane defined by said other end turn, said first end being secured to a wing member and said second end being secured to said conveyor frame, with the axis of said coil spring being offset from the line between the points of securement of said coil spring to said wing member and said conveyor frame for substantial transverse flexure of said coil spring upon pivotal movement of said wing member in either direction from said normal position.
 7. A harvesting machine as set forth in claim 6 wherein each wing member terminates in a trailing edge spaced from the pivotal mounting of said wing member, the trailing edge being generally perpendicular to a line from the pivotal mounting to said trailing edge.
 8. A harvesting machine as set forth in claim 6 wherein said wing members are formed from plastic material having sufficient flexibility to enable said other ends of said wing members to flex upwardly or downwardly a substantial distance transverse to said closure planes.
 9. A harvesting machine as set forth in claim 8 wherein each wing member terminates in a trailing edge spaced from the pivotal mounting of said wing member, the trailing edge being generally perpendicular to a line from the pivotal mounting to said trailing edge.
 10. A harvesting machine as set forth in claim 6 wherein said first and second ends of said coil spring are generally tangent to the end turns from which they extend.
 11. A harvesting machine comprising: a main frame adapted to straddle and move longitudinally along a row of fruit-bearing plants, a pair of conveyor mechanisms carried by said main frame and extending along the length thereof, one on each side of the longitudinal centerline of the machine and both at the same height above the ground, each conveyor mechanism having a frame and a conveyor belt carried thereby, a closure assembly secured to the inner edge of each conveyor frame, said closure assemblies forming closure planes extending inwardly and upwardly at the same angle of inclination from the conveyor frames towards the longitudinal centerline of said machine, each closure assembly comprising a plurality of flat, overlapping wing members spaced along the conveyor frame associated therewith and lying in the closure plane associated therewith, and including means for pivotally mounting each wing member at one end thereof for movement of the opposite free end of the wing member towards and away from said longitudinal centerline with movement of said one end of said wing member being confined to movement in said closure plane, the free ends of said wing members on opposite sides of said longitudinal centerline being normally and randomly overlapped at said centerline, with some wing members on one side of said centerline being overlapped on wing members on the other side of said centerline and vice versa, spring means associated with each wing member for resiliently biasing said free end of said wing members towards said longitudinal centerline, said wing members being formed from plastic material having sufficient flexibility to enable said free ends of said wing members to flex upwardly or downwardly a substantial distance transverse to said closure planes and to enable said wing members to overlap at random at said longitudinal centerline after being pivoted away from and returned to said centerline. 